1. Field of the Invention
This invention relates to a vertical shaft wind turbine, and particularly to an arrangement and installation method of blades that can effectively improve the efficiency of a vertical shaft wind turbine.
2. Description of the Related Art
To make better use of wind energy, wind power generation devices have been developed. These can be divided according to the different position of the rotary shaft of the wind turbine into: horizontal shaft wind turbines and vertical shaft wind turbines.
The wind wheel of a vertical shaft wind turbine comprises straight blade 1 with airfoil-shaped cross section, as shown in FIG. 1. The axial line of blades is parallel to the main shaft, i.e., the vertical shaft 2. Airfoil design is a major facet of aerodynamics. Various airfoils serve different flight regimes.
Conventional asymmetric airfoils used in lifting type vertical shaft wind turbines with fixed blade rotary angle have a convex surface 11 and a concave surface 12. Traditional arrangement of the blade is to orient the concave surface 12 facing toward the vertical shaft 2, as shown in FIG. 2.
However, in fact, it is this incorrect installation that results in poor wind energy utilization rate of vertical shaft wind turbines. Extensive experiments have shown that the existing blade installation method for vertical shaft wind turbines is not most optimal in actual industrial production.
Chinese Pat. No. CN1719023A discloses a wind turbine with a complex action of resistance and lifting. The angle between the chord of the airfoil blade 1 and the blade link rod 2 is 60-70 degrees. The blade rotary angle range corresponds to between 20 and 30 degrees. The action of resistance and lifting is complex due to difference in rotation direction between the resistance type wind wheel and lifting type wind wheel. The vertical wind wheel cannot be made as resistance and lifting type simultaneously.